In our daily lives, various electronic devices such as power adapters, transformers, power supply apparatuses, electrical connectors and the like are widely used. Since the internal electronic components and the circuits of these electronic devices need to be appropriately isolated and protected, these electronic devices are usually covered by a case assembly structure to avoid the contact with the external environment.
Take a power supply apparatus for example. FIG. 1 is a schematic exploded view illustrating a case assembly structure of a conventional power supply apparatus. As shown in FIG. 1, the case assembly structure 10 of the power supply apparatus 1 comprises a first case 11 and a second case 12. The second case 12 has an extension part 121 extended from an edge thereof. Several bolt holes 122 are formed in the extension part 121 of the second case 12. Corresponding to the bolt holes 122, the first case 11 has several bolt holes 111. By penetrating screws 13 through corresponding bolt holes 111 and 122, the first case 11 is combined with the second case 12. Furthermore, the power supply apparatus 1 further has a heat-dissipating element 14 (e.g. a fan) for removing heat generated during operation. The heat-dissipating element 14 has several bolt holes 141. Corresponding to the bolt holes 141, the first case 11 has several bolt holes 112. By penetrating screws 13 through corresponding bolt holes 112 and 141, the heat-dissipating element 14 is fastened on the first case 11.
Since the first case 11 of the case assembly structure 10 of the power supply apparatus 1 has two sets of bolt holes 111 and 112 matching the bolt holes of the second case 12 and the heat-dissipating element 14, the process of fabricating the first case 11 is relatively complicated. For assembling the case assembly structure 10, the bolt holes 111 and 112 of the first case 11 need to be respectively aligned with the bolt holes 122 of the second case 12 and bolt holes 141 of the heat-dissipating element 14. If one or more of the bolt holes 111 and 112 are not precisely aligned with the bolt holes 122 and 141, the case assembly structure 10 fails to be successfully combined together because one or more screws 13 cannot be screwed in corresponding bolt holes. Moreover, the processing of assembling the case assembly structure 10 is not cost-effective because a great amount of screws 13 are required.